How's your Kylo Ren or your R2? Both are better choices. Or, more importantly, how are other people's R2s? If they are good, don't zeta Maul, because it'd be a waste. I actively seek out Maul squads because they are easier to defeat than any other option I have right now. Either way, don't be like me and zeta Tarkin's lead. Sounded cool, but it wasn't.
Savage Opress is a good one and works really well under a Nihilus lead (even without his leadership zeta) if you want to keep your zeta dark sideish. If you're on a newer shard, you'll wreck shop with a zSavage.
Me personally, I switched from Nihilus some time back to Empire to finally selling my soul this week and switching to Rebels.
It's really a depressing time to be an empire/sith fan in this game.
https://swgoh.gg/zeta-report/ will give you an idea of what other people have done, but it's also a bit misleading because of the huge numbers of Vader and Maul. Vader's zeta used to be way better than it is currently, and it's only really good for raids now. Maul got crushed by the release of R2.